A MAP sensor is a key component in modern vehicles. Here, AZoSensors provides an overview of the technology, its use, and the current commercial landscape for these products.
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What is a MAP Sensor?
Modern vehicles rely heavily on the use of advanced electronics and diagnostics to monitor every function within a vehicle and ensure that it is running at optimal performance. Central to how modern automobiles function is the use of increasingly sophisticated sensors for multiple roles.
A MAP sensor, otherwise known as a Manifold Absolute Pressure sensor, is used to measure the density of air in the manifold. This is in contrast with a MAF (Mas Air Flow) sensor, which measures the mass of air flowing to the engine itself.
In engines that require fuel injection to operate, where air and fuel are mixed outside the combustion chamber and are injected into the engine, a MAP sensor is an essential component. Using this type of sensor, the continuous flow of air into an engine can be measured efficiently.
Where is a MAP Sensor Located?
A MAP sensor is located on the engine manifold, usually next to the vehicle’s throttle body or on it. In forced-induction engines, the MAP sensor can be found on the intake tract. This intake tract is located before the engine’s turbo.
How Does a MAP Sensor Work?
Using a MAP sensor in an ICE automobile’s engine allows the vehicle’s electronic control system to calculate the density of air entering the combustion chamber, allowing the onboard computer to optimize the amount of fuel needed for efficient combustion.
A MAP sensor essentially measures the amount of pressure in the manifold fuel intake system. It works in conjunction with the intake air temperature sensor and the engine speed sensor to optimize the precise amount of fuel which needs to be injected.
Intake air pressure is applied to the sensor’s silicon chip, inducing changes in pressure, and changing the MAP sensor’s electrical resistance and output voltage value. The sensor’s internal structure is composed of a sealed vacuum chamber which either has a perfect vacuum or calibrated pressure.
A small, flexible piezoresistive silicon chip is used in the MAP sensor to measure the manifold intake air pressure and provide data for the onboard electronic control system. Intake air pressure causes the chip to deflect, leading to resistance and output voltage changes.
When the engine is initially turned on, the atmospheric pressure inside the manifold determines the air density. Pressure inside the intake manifold reduces once the engine has started, creating a vacuum. Pressing the accelerator pedal causes high pressure, which causes the sensor’s chip to flex upward, changing its resistance.
Similarly, when the brakes are applied by the driver, the pressure decreases in the manifold intake, causing the chip in the MAP sensor to return to its idle position. Consequently, the voltage change in the MAP sensor allows the ECU to calculate the stoichiometrically correct air-fuel ratio.
How to Clean a MAP Sensor
To ensure optimal performance and fuel efficiency, a MAP sensor should be periodically cleaned, as it sits in the engine and is thus subject to built-up dirt. Aside from increasing fuel consumption, a dirty MAP sensor can lead to a jerking motion during acceleration or even vehicle stalling in extreme cases.
After disconnecting the vacuum pipe from the MAP sensor and removing it from the engine, it can be cleaned using a specialist sensor cleaning product, electrical parts cleaner, and a rag, taking care not to scrub the sensor itself. It can then be allowed to dry and reattached to the vehicle’s engine.
MAP Sensors: Commercial Landscape
Whilst there is no specific data on the MAP sensor market’s global value, the global automotive sensor market in 2022 was valued at £40.39 billion. Generally speaking, a MAP sensor will cost between $50 and $200, depending on the make and supplier. Many commercial suppliers exist on the market selling these products.
Some of the main suppliers of this technology include Bosch, Link Engine Management, RTG Automotive, Performance Electronics, and DENSO. Different MAP sensor models are suitable for different types of manifold injection ICE engines and vehicles.
The global automotive sensor market, which includes MAP sensors, is expected to reach $67.2 billion by 2030, with a CAGR of 6.57% predicted between last year (2022) and 2030.
As ICE vehicles are phased out in the coming decades in favor of electric vehicles, the MAP sensor market could take a hit as fewer vehicles are produced which need this technology - electric vehicles do not need to monitor air/fuel mixtures and air pressure as they do not rely on hydrocarbon fuels.
MAP sensors may have a continuing role in future automobile design, however. Hydrogen has been widely explored as an alternative to electric vehicles, and this fuel has similarities with conventional fossil fuels. Recent research has explored the use of MAP sensors in hydrogen engines.
In Summary
Modern automobiles require a complex suite of sensors feeding real-time data back to the onboard ECU to provide optimal fuel efficiency and performance. A MAP sensor is an essential component in manifold fuel injection engines that must be kept clean to provide maximum fuel efficiency.
While the future of automotive technology is increasingly looking electrical in nature, it is likely that some ICE vehicles will persist on the world’s roads for at least the next couple of decades, and hydrogen is increasingly being explored, meaning that the MAP sensor will continue to play a key role in optimizing vehicular performance.
References and Further Reading
Xin, G et al. (2022) Monitoring of hydrogen-fueled engine backfires using dual manifold absolute pressure sensors. International Journal of Hydrogen Research 47:26 pp. 13134-13142 https://www.sciencedirect.com/science/article/abs/pii/S0360319922005936?via%3Dihub
What is a MAP sensor [Online] Easy Car Electrics. Available at: https://www.easycarelectrics.com/what-is-map-sensor/
Making sense of your sensors: MAP sensor [Online] Delphi Autoparts (website). Available at: https://www.delphiautoparts.com/en-gb/resource-center/article/making-sense-of-your-sensors-map-sensor
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